1. Field of Invention
The present invention relates to semiconductor devices, methods for manufacturing the same, circuit substrates and electronic apparatuses.
2. Description of Related Art
The related art includes semiconductor devices in which a plurality of semiconductor chips are stacked one on top of the other. In such related art semiconductor devices, electrical connections can be provided by bonding electrodes of the semiconductor chips to wires. It is important that wires to be connected to a semiconductor chip on an upper side should not contact wires to be connected to a semiconductor chip on a lower side. It is also important to form a trajectory of the wires such that the height of the entire loops of wires is lowered, and the length of wires is shortened. Also, it is necessary to avoid contact between the wires and corner sections of the semiconductor chips.
The present invention addresses or solves the above and/or other problems, and realizes a preferable wire routing.
A semiconductor device in accordance with the present invention includes: leads; a plurality of semiconductor chips stacked in layers; first wires that electrically connect a first semiconductor chip of the plurality of semiconductor chips to the leads; second wires that electrically connect a second semiconductor chip stacked on the first semiconductor chip of the plurality of semiconductor chips to the leads; and first and second bent sections formed in the second wires, each having a curvature greater than other parts thereof. The second wires extend toward the first bent section above the leads, upwardly diagonally extend from the first bent section toward the second semiconductor chip, and downwardly extend from the second bent section to electrically connect to the second semiconductor chip.
In accordance with the present invention, the first and second bent sections are formed in the second wires. The second bent section is formed closer to the second semiconductor chip than the first bent section to the second semiconductor chip, and defines the topmost point in the second wires. As a result, a distance can be secured between the second wires and corner sections of the second semiconductor chip, and contact between the two can be avoided or substantially avoided. Furthermore, the distance between the first and second wires can be adjusted by the first bent section. In other words, the topmost point of the second wires can be made lower and the distance between the first and second wires can be better secured as compared to the case where the second wires directly extend from the leads to the second bent section. Accordingly, routing of the second wires in the shortest length or substantially the shortest length can be realized in low loops.
In the semiconductor device, the second wires may be bonded to electrodes of the second semiconductor chip after having been bonded to the leads.
In the semiconductor device, the first bent section may be formed at a position lower than the height of the first wires.
In the semiconductor device, an angle defined by a tangential line at the first bent section and a surface of the leads on the side of the second semiconductor chip may be smaller than an angle defined by a tangential line at an intermediate section in a height direction of the first wires and the surface of the leads on the side of the first semiconductor chip.
In the semiconductor device, an angle defined by a tangential line at a portion of the second wires in an area from the first bent section toward the leads on the side of the second semiconductor chip may be greater than an angle defined by the tangential line at the intermediate section in the height direction of the first wires and the surface of the leads on the side of the first semiconductor chip.
As a result, the first bent section can be separated from the first wires, such that a distance between the first and second wires can be secured.
In the semiconductor device, the second bent section maybe formed on an inner side of the first semiconductor chip.
In the semiconductor device, the second bent section may be formed at a position higher than the second semiconductor chip by at least a width of the second wires.
As a result, contact between the second wires and corner sections of the second semiconductor chip can be securely avoided.
In the semiconductor device, the second wires may extend to connect the first and second bent sections in generally the shortest distance.
As a result, the second wires can be shortened as much as possible.
In the semiconductor device, the leads may be wiring patterns supported by a substrate.
A circuit substrate in accordance with the present invention has the semiconductor device described above mounted thereon.
An electronic apparatus has the semiconductor device described above.
A method for manufacturing a semiconductor device in accordance with the present invention includes: forming first wires that electrically connect a first semiconductor chip of a plurality of semiconductor chips to leads; forming second wires, which electrically connect a second semiconductor chip stacked on the first semiconductor chip of the plurality of semiconductor chips to the leads, with first and second bent sections, each having a curvature greater than other parts thereof; and leading the second wires to extend toward the first bent section above the leads, to extend upwardly diagonally from the first bent section toward the second semiconductor chip, and to extend downwardly from the second bent section to electrically connect to the second semiconductor chip.
In accordance with the present invention, the second wires having the first and second bent sections are formed. The second bent section is formed closer to the second semiconductor chip than the first bent section to the second semiconductor chip, and defines the topmost point in the second wires. As a result, a distance can be secured between the second wires and corner sections of the second semiconductor chip, and contact between the two can be avoided or substantially avoided. Furthermore, the distance between the first and second wires can be adjusted by the first bent section. In other words, the topmost point of the second wires can be made lower and the distance between the first and second wires can be better secured as compared to the case where the second wires are led directly from the leads to the second bent section. Accordingly, routing of the second wires in the shortest length or substantially the shortest length can be realized in low loops.
In the method for manufacturing a semiconductor device, the first bent section may be formed at a position lower than the height of the first wires.
In the method for manufacturing a semiconductor device, the second wires may be formed such that an angle defined by a tangential line at the first bent section and a surface of the leads on the side of the second semiconductor chip is smaller than an angle defined by a tangential line at an intermediate section in a height direction of the first wires and the surface of the leads on the side of the first semiconductor chip.
In the method for manufacturing a semiconductor device, the second wires may be formed such that an angle defined by a tangential line at a portion of the second wires in an area from the first bent section toward the leads on the side of the second semiconductor chip is greater than an angle defined by the tangential line at the intermediate section in the height direction of the first wires and the surface of the leads on the side of the first semiconductor chip.
As a result, the first bent section can be separated from the first wires, and therefore a distance between the first and second wires can be secured.
In the method for manufacturing a semiconductor device, the second bent section may be formed on an inner side of the first semiconductor chip.
In the method for manufacturing a semiconductor device, the second bent section may be formed at a position higher than the second semiconductor chip by at least a width of the second wires.
As a result, contact between the second wires and corner sections of the second semiconductor chip can be securely avoided.
In the method for manufacturing a semiconductor device, the second wires may be led to connect the first and second bent sections in generally the shortest distance.
As a result, the second wires can be shortened as much as possible.
In the method for manufacturing a semiconductor device, the leads may be wiring patterns supported by a substrate.